Extracellular matrix assessment of infected chronic venous leg ulcers: role of metalloproteinases and inflammatory cytokines

Chronic venous ulcer (CVU) represents a dreaded complication of chronic venous disease (CVD). The onset of infection may further delay the already precarious healing process in such lesions. Some evidences have shown that matrix metalloproteinases (MMPs) are involved and play a central role in both CVUs and infectious diseases. Two groups of patients were enrolled to evaluate the expression of MMPs in infected ulcers and the levels of inflammatory cytokines as well as their prevalence. Group I comprised 63 patients (36 females and 27 males with a median age of 68.7 years) with infected CVUs, and group II (control group) comprised 66 patients (38 females and 28 males with a median age of 61.2 years) with non-infected venous ulcers. MMP evaluation and dosage of inflammatory cytokines in plasma and wound fluid was performed by means of enzyme-linked immunosorbent assay test; protein extraction and immunoblot analysis were performed on biopsied wounds. The first three most common agents involved in CVUs were Staphylococcus aureus (38.09%), Corynebacterium striatum (19.05%) and Pseudomonas aeruginosa (12.7%). In this study, we documented overall higher levels of MMP-1 and MMP-8 in patients with infected ulcers compared to those with uninfected ulcers that showed higher levels of MMP-2 and MMP-9. We also documented higher levels of interleukin (IL)-1, IL-6, IL8, vascular endothelial growth factor and tumour necrosis factor-alpha in patients with infected ulcers with respect to those with uninfected ulcers, documenting a possible association between infection, MMP activation, cytokine secretions and symptoms. The present results could represent the basis for further studies on drug use that mimic the action of tissue inhibitors of metalloproteinases in order to make infected CVU more manageable.